Vacuum tube



June 13, 1933. R RANGER 1,913,954

- VACUUM TUBE Original Filed Dec. 18, 1 922 Hm: I 3 swim I g INVENTOR R. H. RANGER ATTORNEY Patented June 13, 1933 UNITED STATES PATENT OFFICE RICHARD ROWLAND RANGER, OF NEWARK, NEW JERSEY, ASSIGNOB TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE VACUUM TUBE Original application filed December 18, 1922, Serial No. 607,478. Divided and this application filed I June 11, 1929.

This specification forms a divisional part of my copending application, Serial No. 607,47 8, filed December 18, 1922 now Patent No. 1,788,392, relating to Interference reducing means for radio receiving apparatus.

This invention relates to improved means for combining signals received from the same station on a plurality of aerials, and more specifically, to means for controlling the space current in a vacuum tube detector or amplifier in accordance with such signals, in such away that the tubes will respond only to signals which have a predetermined phase relationship.

It is an object of this invention to provide such means which will decrease the interfering eifects caused by static disturbances and which Will also reduce the interferingeflects caused by the operation of another transmitting station on substantially the same wave length as the station desired. It is a further object of this invention to provide means for geographically tuning to select one particular transmitting station from among several transmitting on substantially the same wave length. It is a further objectof this invention to provide such means which shall have a sharper tuning characteristic than the arrangements now used for the purpose, and

which shall, at the same time, be relatively inexpensive, simple to construct and install and which shall be reliable and positive in its operation. Still other objects will be apparent from the specification.

My invention is shown by way of example in the accompanying drawing and is explained in the specification with reference to the embodiment illustrated and itsunderlying principles will best be und-erstoodby reference to the specification and drawing but the scope will be particularly pointed out in the accompanying claims.

Referring to the drawing:

Figure 1 is a diagram showing the relative position of sending, receivingand recording stations; 7

Figure 2 is a diagrammatic comparison of the addition law of an arrangement old in the art as shown in dotted lines and of my invention as shown in full lines;

Serial No. 369,979. I

Figure 3 is a diagram of the circuit embodyingmy invention; and,

Figure 4 is a diagrammatic elevation view of the filament and grid of a vacuum tube according to my invention;

Figure 5 is aplan View of the same. Referring to Figure 1, let A represent a transmitting station, B and B two receiving stations connected by wire lines to the. common indicatingapparatus at C and let D be a second transmitting station. "It-is Well knownin' the art that as a wave from station A travels along, as shown in dotted lines, it will first be taken up at station B and later be taken up at B. This difference in time may be very small but it is, nevertheless, sufiicient for certain arrangement of the receiving station with reference to the transmitting station, to produce large differencein phase at the indicating apparatus ,70 C Where the signals are combined. It has been'suggested' that in order to obtain 1naXi mum signal response fromthe desired transmitting station the signals should be brought into phase With each other and added together and the resultant signal thereby obtained utilized toactuate the detector. It has which are out of phase by, a substantial amount the response may be almost asgreat as if the signals were absolutely in phase.

While this arrangement is satisfactory when the signals from the interfering station have a relatively large phase difference it will not prevent interference when the phase difference of the signals is relatively small.

Y My invention provides means for overcoming this'difiiculty and achieving a resultant curve such as shown in full lines in Figure-2.

It will be seen by comparison of the curves of Figure 2that by the use of, apparatus hav- L as ing the characteristic shown in full lines, it is possible to obtain much greater selectivity as regards interfering stations when the interfering station is situated relatively close to the desired transmitting station so that the off to a very much greater extent than would be expected. For instance, if a grid consists of 10 parallel sections of wire and one of these sections breaks, the drop in efficiency is considerably over 10%. I make use of this phenomenon to provide that no response will he obtained from the indicating apparatus unless the signals received at the common indicating means have a desired and predetermined phase relation and this is done as follows:

Referring to Figure 3, B and B respectively designate two receiving aerials having different characteristics in one or more respects. For instance, they may be located at different distances from the transmitting station, or they may have different directional characteristics or they may have different electrical characteristics, with reference to tuning, damping, etc. Each aerial is provided with the usual tuning means such as, variable inductances 1 and 1' and variable condensers 2 and 2. The signals received upon these aerials may be amplified by the use of any suitable means known in the art if desired or they may be transmitted over the wire lines to the indicating apparatus at C without amplification, depending upon circumstances. The indicating apparatus provided at C comprises a multiple section grid amplifier tube designated as 3. This tube comprises a hot cathode and an anode according to the well known construction but is provided with a plurality of electrically independent grids 4 and 4. I preferably arrange these grids as diagrammatically shown in Figs. 4 and 5, in such a way that each horizontal section of the grid is in the form of an ellipse enclosing the filament, this section being attached at one end to the conducting post P, which leads to a contact stud (not shown) in the base of the tube. As shown by Fig. 4, the sections of the grid are connected alternately to posts P and P, the post P also leading to another contact stud in the base of the tube. The signals received from station B are impressed across the cathode of tube 3 and the grid 4 whereas signals from station B are impressed across the cathode of the tube 3 and the grid 4. Connected in the output circuit of this amplifier, I provide a coupling coil 5 for the purpose of impressing the combined signal from amplifier 3 upon a suitable detector 6 provided with any suitable indicating or recording means, herein shown as telephone receivers 7. The amplifier tube 3 is operated at such point of its characteristic that the combined action of grids 4 and 4 is required to render it operative; that is to say signals must be in phase on grids 4 and 4 in order to produce response of the amplifier.

Turning now to the operation of my receiving apparatus, if it is desired to receive signals from station A the phase shifting means will be so adjusted as to bring the signals from A into phase with each other at C as pointed out above. This condition corresponds to maximum response of the indicating apparatus. Let it now be assumed that it is desired to receive signals from station D. The phase shifting means will be adjusted to bring signals from this station into phase at C. It will be apparent that signals received from station A. will no longer be in phase at C and therefore will not be reproduced in the output circuit of the amplifier and hence will not affect the indicating or recording apparatus.

It will be seen that I have provided means whereby the combined action of both aerials giving oscillations having predetermined phase relation is required to cause response of the indicating or recording means. This property is of advantage in preventing re sponse of the indicating means to static disturbances since it will beapparent that the only static disturbances which can be passed through the amplifier 3 is a disturbance which has the same phase. relationship as that of the signal desired and .it will be seen also that this will prevent disturbance due to any signal or static which is received upon only one antenna.

While I have shown and described tube 3 as an amplifier, it will be apparent that similar results may be obtained by operating this tube as a detector, and that the number of aerials to be used may be increased by providing a grid section for each aerial. Still other modifications and changes may be made as will be apparent to anyone skilled in the art without departing from the spirit of 1 my invention.

Having now described my invention, what I claim and desire to secure by Letters Patent is the following:

1. An electron discharge device comprising a cathode, a plurality of grid members surrounding the cathode and a plate surrounding the grid members, a support for each grid member equally spaced from said cathode, a series of looped conductors attached to each support, the looped conductors of each series being intermeshed with those of the other series, the cathode being disposed eccentrically with respect to each looped conductor series but symmetrically arranged with respect to both series when considered as a single unit.

2. An electron discharge device comprising a cathode, a pair of grid members surrounding the cathode and a plate surrounding the grid members, a support for each grid member equally spaced from said cathode, a series of looped conductors attached to each support, the looped conductors of one series being intermeshed with those of the other series, the cathode being disposed eccentrically with respect to each looped conductor series but symmetrically arranged with respect to both series when considered as a single unit.

3. An electron discharge device comprising a cathode, a pair of grid members surrounding the cathode and a plate surrounding the grid members, each grid member comprising a support and a series of looped conductors attached thereto, the looped conductors of one series being intermeshed with those of the other series, the cathode being disposed eccentrically with respect to each looped conductor series but symmetrically arranged with respect to both series when considered as a single unit.

RICHARD HOWLAND RANGER. 

